The steroid hormones present in many generations of combined oral contraceptives (COC) can act as endocrine disruptors inducing changes in the behavior and physiology of fish. In this context, the aim of this work was to evaluate the effects of steroid hormones present in COC on behavioral parameters of Betta splendes, an aggressive ornamental fish used in the aquariophily. Adult males were observed with the ad libitum method to develop an ethogram and were divided into five groups, Control and exposed to hormones: 17β-estradiol (E2), levonorgestrel and ethinylestradiol (LEA - 2nd COC generation), gestodene and ethinylestradiol (GEA - 3rd COC generation) and drospirenone and ethinylestradiol (DEA - 4th COC Generation). Fish were exposed for 30 days to a final concentration of 10ng/L. The behavior was evaluated by scan sampling and animal-focal methods, and feed intake. In the scan sampling method, the Resting behavior showed the highest value (54.4±10.1%) in E2 group (P<0.05). The aggressive behavior Rush (16.1±3.6%) and Back and Rush (16.4±5.1%) showed the highest values in the control group, compared to the other groups (P<0.05). Animals in the E2 group showed higher frequency of inactive behaviors (76.1%) compared to other groups. Furthermore, the atypical behavior Erratic swimming was not observed in the control group, but it was observed in the experimental groups. The E2, LEA, GEA and DEA groups showed reduction in aggressive behavior (10%) compared to the control group by the animal-focal method. Moreover, no difference was observed in the exhibition of these behaviors and feed intake comparing animals exposed to the different generations of contraceptives. It can be concluded that 17β-estradiol has caused more effects on fish and different generations of COC showed similar toxic effects in the observed behaviors.
betta splendens; estradiol; ethinylestradiol; ethogram; aggressive behavior
